Vitruvian precursor for gas phase deposition: structural insights into iridium β-diketonate volatilities

New data on the thermodynamic properties of the melting and sublimation of a series of volatile iridium(i) complexes [Ir(cod)(L)] with cyclooctadiene-1,5 (cod) and beta-diketones (L = RC(O)CHC(O)R ') have been obtained with differential scanning calorimetry and vapor pressure measurements. Combining experimental, empirical and theoretical methods, ways to estimate difference in heat capacities between gas and crystal phases have been suggested. An effect on the volatility in introducing the simplest alkyl, fluorinated alkyl and aryl terminal groups (R and R ') into the chelate ligand has been explained in terms of a detailed crystal packing analysis supported by a quantum chemical calculation of crystal lattice energies. To reveal the influence of the coordination center, the thermal behavior of complexes was compared with that for the tris-chelates, [Ir(L)(3)]. The study broadens our understanding of relationships between the structure and thermal properties of volatile precursors, which is useful for further tuning effective compounds for metal-organic chemical vapor deposition purposes.

Automated summary

New data on the thermodynamic properties of a series of volatile iridium(i) complexes have been obtained, suggesting ways to estimate the difference in heat capacities between gas and crystal phases. The influence of different terminal groups on the volatility of the complexes was explained through detailed crystal packing analysis and quantum chemical calculation of crystal lattice energies. This study broadens our understanding of the relationship between the structure and thermal properties of volatile precursors, which is useful for further tuning effective compounds for metal-organic chemical vapor deposition purposes.